Radar Interference due to ADS-B can create hindrances in normal operations of a radar system.Air Traffic Control (ATC) radar systems are critical for ensuring the safety and efficient operation of air traffic. However, these systems can be subject to interference from other sources, including Automatic Dependent Surveillance-Broadcast (ADS-B) systems.
ADS-B Interference and False Target
ADS-B is a technology that allows aircraft to transmit their position, velocity, and other information to ground stations and other aircraft. The information is transmitted via a 978 MHz or 1090 MHz radio signal, which can interfere with ATC radar systems that operate in the same frequency range. This interference can result in false targets being displayed on the radar, which can create confusion and lead to safety hazards.
ADS-B Interference with ATC Radar System
There are several ways in which ADS-B signals can interfere with ATC radar systems.
Ghosting
One of the most common forms of interference is known as "ghosting", which occurs when the radar system receives a signal that is delayed or reflected by an object such as a building or hill. This can cause the radar to display a false target that is separated from the actual aircraft by a significant distance.
Clutter
Another form of interference is known as "clutter", which occurs when the radar system receives a signal that is reflected by a non-moving object such as a building or tree. This can cause the radar to display a false target that is stationary and does not move with the actual aircraft.
Issues Reported from ADS-B Interference incidents
There have been several reported incidents of interference caused by ADS-B signals in air traffic control services. Some of the common issues reported include
Interference with radar systems
ADS-B signals can interfere with radar signals, causing degradation of radar performance and disruption of air traffic control and flight safety.
Interference with communication systems
ADS-B signals can also interfere with communication systems used by air traffic control, leading to communication failures.
Interference with navigation systems
In some cases, ADS-B signals have been reported to interfere with navigation systems, causing incorrect positioning information to be displayed.
These incidents highlight the importance of ensuring compatibility and avoiding interference between ADS-B and other radio frequency systems used in air traffic control services. Industry standards and best practices, as well as ongoing monitoring and testing, help to minimize the risk of such incidents.
Mitigation of the Effect of Interference from ADS-B Signals
To mitigate the effects of interference from ADS-B signals, ATC radar systems can use techniques such as
Frequency Discrimination
Frequency discrimination involves using filters to block or reduce the intensity of signals that are outside the radar's operating frequency range.
Time Discrimination
Time discrimination involves using filters to block or reduce the intensity of signals that are delayed or reflected.
Signal Processing
Signal processing involves using algorithms to analyze the radar's signals and detect and remove false targets.
Measures Implemented By Federal Aviation Administration
The Federal Aviation Administration (FAA) has also implemented several measures to minimize the impact of ADS-B interference on ATC radar systems. One of these measures is to require aircraft to transmit their position and velocity information using the 978 MHz frequency, which is less susceptible to interference than the 1090 MHz frequency. The FAA has also developed procedures for identifying and resolving interference issues, and has established a program to provide funding for the installation of interference mitigation equipment at ATC radar sites.
Growing Concern
Despite these efforts, interference from ADS-B signals continues to be a concern for ATC radar systems. In addition to the safety hazards, interference can also lead to an increased workload for air traffic controllers and reduced capacity for the national airspace system.
Software Defined Radio Technology
Research is being conducted to develop new technologies and techniques that can further reduce the impact of ADS-B interference on ATC radar systems. One promising approach is the use of software-defined radio (SDR) technology, which allows the radar system to adapt to changing interference conditions in real time.
How Radar Interference due to ADS-B is depicted
Automatic Dependent Surveillance-Broadcast (ADS-B) radar interference can manifest in various ways. Some common patterns of interference include
False targets
In some cases, the radar may detect false targets that are not present in the airspace. These false targets can be caused by reflections or delays in the signal from buildings or other structures.
Increased noise
The radar may detect an increase in noise or background clutter, making it more difficult to detect actual targets.
Loss of targets
In some cases, the radar may lose the ability to detect actual targets due to interference.
Reduced range
The range of the radar may be reduced due to interference, making it more difficult to detect targets at a distance.
Interference on specific radar frequency
The interference may occur on specific frequencies like 978 MHz or 1090 MHz which are used by the ADS-B systems.
Interference on specific azimuth or elevation
The interference may occur in specific azimuth or elevation, which can be caused by buildings or other structures that are reflecting or delaying the signal.
Interference at a specific time of the day
The interference may occur at specific times of the day, which can be caused by factors such as changes in atmospheric conditions or the movement of mobile buildings or other structures.
It's important to note that the pattern of interference can vary depending on factors such as the location of the radar, the type of radar being used, and the type and intensity of the interference. ATSEP should conduct regular monitoring of interference patterns to identify the cause and take necessary actions to rectify the issue.
Important steps to be considered by ATSEP for rectification of Interference caused by ADS-B
Air Traffic Service Engineering Personnel (ATSEP) play a critical role in identifying and rectifying interference issues caused by Automatic Dependent Surveillance-Broadcast (ADS-B) systems on Air Traffic Control (ATC) radar systems. Here are some steps that ATSEP can take to rectify interference issues caused by ADS-B
Identify and locate the source of interference
ATSEP can use spectrum analyzers and other equipment to locate and identify the source of interference, whether it is from an aircraft or a ground-based system.
Implement frequency discrimination
ATSEP can use filters to block or reduce the intensity of signals that are outside the radar's operating frequency range. This can help to reduce the impact of interference from signals transmitted on the 978 MHz or 1090 MHz frequencies.
Implement time discrimination
ATSEP can use filters to block or reduce the intensity of signals that are delayed or reflected. This can help to reduce the impact of interference caused by ghosting or clutter.
Implement signal processing
ATSEP can use algorithms to analyze the radar's signals and detect and remove false targets. This can help to further reduce the impact of interference.
Coordinate with the FAA
ATSEP can work with the Federal Aviation Administration (FAA) to resolve interference issues and implement mitigation measures. The FAA has established procedures for identifying and resolving interference issues and can provide funding for the installation of interference mitigation equipment at ATC radar sites.
Use software-defined radio technology
ATSEP can use software-defined radio (SDR) technology to adapt the radar system to changing interference conditions in real time.
Use advanced signal processing techniques
ATSEP can use advanced signal processing techniques such as Machine Learning, Adaptive Filters, etc to reduce the impact of interference on ATC radar systems.
Regular Maintenance
ATSEP can perform regular maintenance of the radar system including cleaning and calibration, to ensure that it is operating correctly and efficiently.
Conduct Training
ATSEP can conduct regular training sessions for air traffic controllers and other personnel, to ensure that they are aware of the potential impact of interference and know how to respond to it.
Ultimately, it is important for ATSEP to stay current with the latest technologies and techniques for mitigating interference, and to work closely with the FAA and other stakeholders to ensure the safety and efficient operation of the national airspace system.
Preventive Measures
Implementing an interference management system
ATSEP can implement an interference management system that can detect and resolve interference issues in real-time.
Use of advanced technologies
Using advanced technologies such as beam forming and smart antenna can help in reducing the interference.
SkyRadar's System Monitoring & Control Solution
SkyRadar is continuously embracing new trends in its system monitoring & control solution. The Use-cases on errors and system malfunctions, described in this series are or will be implemented in SkyRadar's SkySMC training system. Implementations are consisting of
- real hardware like training radars, transmitters, receivers, UPSs, networks,
- virtualized hardware like virtual servers, networks, applications
- simulated solutions like various tower and radar designs
- or a mixture of all three
SkySMC - SkyRadar’s System Monitoring and Control Suite is a pedagogically enhanced, fully operational monitoring & control tool. We have optimized it to cater for the ATSEP-SMC training compliant to EASA's Easy Access Rules for ATM-ANS (Regulation (EU) 2017/373) and ICAO Doc 10057.
SkyRadar provides SkySMC as a complete laboratory in a turn-key approach, or as a service.
SkySMC is not a simulator, but a fully operational open monitoring system. It comes by default with a server including various virtualized applications and virtualized servers, but also connects to simulated systems. In addition, there are various hardware extensions available including training infrastructures, monitorable training radars, or even complete ATM systems, all connected to the System Monitoring & Control solution.
SkyRadar's System Monitoring & Control training system can be easily blended into distance learning solutions.
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